Evaporator for refrigerating systems



March 13, 1934. w, E, BEUNE 1,951,007 I EVAPORATOR FOR REFRIGERATING SYSTEMS Filed June 27. 1932 2 Sheets-Sheet 1 INVENTOR ATTORNEYS March 13, 1934. w E, BEUNE V 1,951,007

EVAPORA'I'OR FOR REFRIGERATING SYSTEMS Filed June 27 1932 2 Sheets-Sheet 2 INVENTOR lVaZfer Zf Bali/2e BY ATTORNEYS Patented Mar. 13, 1934 UNITED STATES EVAPORATOR FOR- REFRIGEBATING SYSTEMS Walter E. Bcline, 'Carbondale, Pa., assignor to Carbondale Machine Company, Carbondale,

Pa., a corporation of Pennsylvania Application June 27, 1932, Serial No. 619,434

8 Claims.

The invention relates to evaporators adapted for use in refrigerating apparatus, and adapted to be flooded with a volatile refrigerant. In such evaporators, the ebullition temperature of the liquid refrigerant at any point in the evaporator varies in accordance with the static liquid head at that point, this temperature increasing as the static liquid head increases.

Also, in evaporator-s, of the flooded type, surges in the liquid level are frequently created due to violent boiling caused by over-feeding of the liquid, sudden loading of the evaporator, or sudden lowering of the evaporator pressure. These surges or violent boiling cause some of the liquid to be carried over with the gas to the compressor.

This condition is apt to cause the head of thecompressor to blow oil, and decreases the capacity of said compressor.

Asan important feature of the present invention, the evaporator is formed of superposed sections so that the static liquid head of the refrigerant is considerably reduced, and each section includes a drum which provides for the ample separation of the gaseous refrigerant from the liquid, and ample space for surges in the liquid. As another important feature of the present invention, the liquid refrigerant is fed into the highest section of the evaporator, and made to overflow successively at predetermined levels into the lower sections, the level of liquid in the lowest section being maintained by a float valve acted upon by the liquid in said latter section and controlling the feed into the highest section.

By the use of the present invention, an extreme- 5 ly low uniform temperature is produced throughout the coils, and the compressors are operated with a high suction pressure, and with the least amount of power. An apparatus of this type is found suitable for temperatures as low as minus 75 F., and may be advantageously used for freezing brine cartridges, hardening packaged ice' cream, and for other similar purposes where extremely low temperatures are required.

In the accompanying drawings, there is shown 5 for the purpose of illustration, one embodiment ofthe present invention. In these drawings Fig. 1 is a vertical section taken through a refrigerating room, and showing an evaporator embodying the present invention, and

Fig. 2 is a section taken on line 2--2 of Fig. 1. The evaporator embodying the present invention is shown as applied to the cooling of a storage or refrigerating room 10, and comprises a plurality of cooling sections or units arranged to reduce the static liquid head without reducing the overall height of the cooling coils. These cooling sections are supplied with liquid refrigerant such as ammonia from a main horizontal (1111111 11 having an inlet conduit 12 for the liquid refrigerant and an outlet conduit 13 leading the gas to the compressor. This drum serves as a header and is large enough to provide for the ample separation of the gas from the liquid refrigerant, and to provide for the surges of liquid created by the variations in load or pressure.

In the specific form'shown, there are provided two similar units arranged at opposite ends-of the drum 11, and each comprising three cooling sections 14, 15 and 16 disposed at different levels. The top cooling section 14 is constructed to provide for the circulation of liquid refrigerant therein, and includes a horizontally extending liquid header 17 spaced below the drum 11 and connected to said drum by a pipe 18 extending from the top of the header to the bottom of the drum. The refrigerant is circulated through a series of coils 20 connected between the upper portion of the drum 11 and the header 1'1.

The cooling section 15 includes a horizontal separating drum 21 spaced below the main drum 11, and supplied with liquid refrigerant from said drum by means of an pipe 23 having overflow its upper end extending through the .bottom of said main drum to a point above said bottom, and

its lower end extending to the lower portion of said drum 21. The height of the overflow pipe 23 above the bottom of the main drum 11 determines the level of liquid in said main drum.

The cooling section 15 includes a horizontal liquid header 24 similar to the header 17 and connected to the drum 21 by means of a pipe- 25. A series of coils 26 similar to the coils 20 are provided between the liquid header 24 and the drum 21, whereby liquid refrigerant is'nirculated from the drum 21 downwardly through the pipe 25, into the header 24, and then upwardly through the coils 26.

The lower section 16 is similar to the section 15, and includes a horizontal separating drum 2'! supplied with refrigerant from the drum 21 through an overflow pipe 28 having the upper end thereof extending through the bottom of said drum to a predetermined height, and having the lower end thereof extending to the lower portion of the drum 27. The cooling section 16 also includes a horizontal header 30 connected to the separating drum 2'! by pipes 31 extending from the bottom of said separating drum 27. to the top of said header. Connected between the header 30 and, the drum 27 is a series of coils 32 similar to the coils and 26 so that the liquid flows downwardly through pipes 31 into the header and then upwardly through and evaporated in the coils 32, the gas and the liquid carried thereby flowing into the separating drum 27.

The gas pressure in the evaporator is maintained uniform throughout the cooling sections, and for that purpose there is provided a gas riser 33 extending from the top of the separating drum 21 to the gas space of the main drum 11, and a gas riser 34 extending from the top of the separating drum 2'7 to the gas space of the separating drum 21. By means of these connections, the gaseous refrigerant is permitted to escape upwardly through the gas risers into the main drum 11, and out through the outlet connection 13 to the compressor. 1

The feed of liquid through the inlet 12 is controlled by means of a valve 36 controlled by a float (not shown) in a float chamber '37. The float, chamber is connected to the header 30 by a pipe 38, and the gas space in said float chamber is connected to the gas space of the separating drum 21 by a conduit 39. This valve 36 is controlled in accordance with the level of liquid in the separating drum 27, so that when the liquid in the lower section 16 has reached a predetermined level, the valve 36 is closed and further feeding of liquid into the main drum 11 is discontinued, or is partially closed to regulate the feed of refrigerant in accordance with the rate of evaporation. Flash gas passing through the valve 36 goes through the inlet pipe 12, into the main drum 11, and out through the connection 13 to the compressor. An equalizing connection 40 may be provided between the headers 30, and may form branch connections from the connection 38.

When the upper section 14 is filled to a predetermined level, the liquid overflows into the middle section 15 through the overflow pipe 23. When the liquid has attained a predetermined level in the middle section 15, the liquid overflows through the overflow pipe 28 into the lower section which fills up to the level determined by the valve 36. By this arrangement, the levels in the upper sections are fixed by the levels of the overflow pipes, and a proper level is maintained in the lowest section by its connection with the float valve.

The drums 11, 21 and 27 serve not only as headers for the coils by means of which recirculation in each of the cooling sections may be effected, but are also made large enough to provide ample space for the separation of gas from the liquid, and to provide for surges which occur in the system due to 'variations in load and pressure. I have found that a drum large enough to provide for the surge of the refrigerant of approximately 40% of the total charge of the refrigerant in its cooling section, will be satisfactory. Also, by dividing the evaporator into a number of cooling sections, the length of coil for each section is reduced, thereby reducing the friction which would hinder the gravity circulation of refrigerant in the coils.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

1. An evaporator of the flooded type for a refrigerating system, including a plurality of vertically spaced horizontal drums, evaporation conduits each having its inlet and its outlet connected to the same drum,-an inlet connection for the highest drum, overflow pipes between said drums for feeding liquid refrigerant successively downwardly.from one drum to another, and a float valve connected to said inlet connection and controlled by the level of liquid in the lowest drum.

2. An evaporator of the flooded type for a refrigerating system, including a plurality of vertically spaced horizontal drums, evaporation conduits each having its inlet and its outlet connected to the same drum, an inlet connection for the highest drum, overflow pipes between said drums for feeding liquid refrigerant sucessively downwardly from one drum to another, a float valve connected to said inlet connection and controlled by the level of liquid in the lowest drum, and gas risers between the gas space of adjoining drums and independent of and spaced from said overflow pipes.

3. An evaporator of the flooded type for a refrigerating system, including a plurality of superposed coil sections, each having a header connected to the inlet and the outlet thereof, an inlet connection for the header of the highest section, overflow pipes between said headers for feeding liquid refrigerant downwardly to said sections in succession, and a float valve connected to said inlet connection and controlled by the level of liquid in the lowest section.

4. An evaporator of the flooded type for a refrigerating system, including a plurality of superposed circulatory units, each including 9.1

horizontally extending drum and a conduit extending downwardly from the lower portion of the drum and then upwardly to the upper portion of the drum, whereby liquid refrigerant is circulated through said conduit, an inlet connection for the highest drum, and pipe connections between the drums, whereby the liquid is fed successively downwardly from one drum to the next.

5. An evaporator 01 the flooded type for a refrigerat ng system, including a plurality of superposed cooling units, each including a pair of vertically spaced horizontal headers, the'upper header being large enough to provide for the separation of gas from the liquid refrigerant, and to provide for surges in the liquid refrigerant due to variations in load and pressure, and an evaporating coil having its opposite ends connected to said headers, an inlet connection for the highest unit, means for feeding the liquid refrigerant downwardly successively through the various units, and separate means for passing the gas upwardly successively through the several units.

6. An evaporator of the flooded type for a refrigerating system, including a plurality of superposed cooling units, each including a pair of vertically spaced horizontal headers, a plurality of coils having their opposite ends connected to said headers, and a connection between said headers whereby liquid refrigerant may flow by gravity downwardly from the upper header to the lower header through said connection, and then upwardly through the coils to the upper header, means for feeding liquid refrigerant to the highest cooling unit, a pipe between the upper headers of adjacent units for feeding liquid refrigerant downwardly to said units in succession, and a pipe between the upper headers of adjacent units for passing gas upwardly to said units in succession.

7. An evaporator of the flooded type for a refrigerating system, including a plurality of superposed cooling units, each including a pair of vertically spaced horizontal headers, a plurality of coils between said headers, and a connection between said headers whereby liquid refrigerant may flow by gravity downwardly from the upper header to the lower header through said connection, and then upwardly through the coils to the upper header, an inlet connection for liquid refrigerant to the highest cooling unit, an overflow pipe between the upper headers of adjacent units for feeding liquid refrigerant successively downwardly in each of said units, a gas pipe connecting the upper parts of the upper headers in series, and a float valve connected to said inlet connection and controlled by the level of liquid in the lowest unit.

8. An evaporator of the flooded type for a refrigerating system, including a plurality of superposed circulatory units, each including a pair of vertically spaced horizontal headers, the upper header being larger than the lower header, a plurality of coils between said headers and having the upper portions thereof connected to the upper portion of the upper header, a connection between said headers whereby liquid refrigerant may flow by gravity downwardly from the upper header to the lower header, and upwardly through the coils to the upper header, an inlet connection to the upper header of the highest unit, an overflow pipe between adjoining units for feeding liquid refrigerant successively downwardlyin each of said units, and a float control valve connected to said inlet connection and controlled by the level of liquid in the lowest unit.

WALTER E. BELINE. 

